// Copyright 2016 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Flags: --expose-gc --allow-natives-syntax

// The test requires a precise GC, which cannot be guaranteed if conservative
// stack scanning is enabled, in the presence of background threads.
// See https://crbug.com/441654955.
//
// Flags: --no-conservative-stack-scanning

d8.file.execute("test/mjsunit/wasm/wasm-module-builder.js");

// Use global variables for all values where the test wants to maintain strict
// control over value lifetime. Using local variables would not give sufficient
// guarantees of the value lifetime.
var module;
var instance1;
var instance2;
var instance3;
var instance4;

(async function () {
  (function CompiledModuleInstancesInitialize1to3() {
    var builder = new WasmModuleBuilder();

    builder.addMemory(1, 1);
    builder.addImport("", "getValue", kSig_i_v);
    builder.addFunction("f", kSig_i_v)
      .addBody([
        kExprCallFunction, 0
      ]).exportFunc();

    module = new WebAssembly.Module(builder.toBuffer());

    print("Initial instances=0");
    assertEquals(0, %WasmGetNumberOfInstances(module));
    instance1 = new WebAssembly.Instance(module, { "": { getValue: () => 1 } });

    print("Initial instances=1");
    assertEquals(1, %WasmGetNumberOfInstances(module));
    instance2 = new WebAssembly.Instance(module, { "": { getValue: () => 2 } });

    print("Initial instances=2");
    assertEquals(2, %WasmGetNumberOfInstances(module));
    instance3 = new WebAssembly.Instance(module, { "": { getValue: () => 3 } });

    print("Initial instances=3");
    assertEquals(3, %WasmGetNumberOfInstances(module));
  })();

  (function CompiledModuleInstancesClear1() {
    assertEquals(1, instance1.exports.f());
    instance1 = null;
  })();

  // Here and below, we need to invoke GC asynchronously and wait for it to
  // finish, so that it doesn't need to scan the stack. Otherwise, the objects
  // may not be reclaimed because of conservative stack scanning and the test
  // may not work as intended.

  // Note that two GC's are required because weak slots clearing is deferred.
  await gc({ type: 'major', execution: 'async' });
  await gc({ type: 'major', execution: 'async' });
  print("After gc instances=2");
  assertEquals(2, %WasmGetNumberOfInstances(module));

  (function CompiledModuleInstancesClear3() {
    assertEquals(3, instance3.exports.f());
    instance3 = null;
  })();

  // Note that two GC's are required because weak slots clearing is deferred.
  await gc({ type: 'major', execution: 'async' });
  await gc({ type: 'major', execution: 'async' });
  print("After gc instances=1");
  assertEquals(1, %WasmGetNumberOfInstances(module));

  (function CompiledModuleInstancesClear2() {
    assertEquals(2, instance2.exports.f());
    instance2 = null;
  })();

  // Note that two GC's are required because weak slots clearing is deferred.
  await gc({ type: 'major', execution: 'async' });
  await gc({ type: 'major', execution: 'async' });
  print("After gc instances=0");
  assertEquals(0, %WasmGetNumberOfInstances(module));

  (function CompiledModuleInstancesInitialize4AndClearModule() {
    instance4 = new WebAssembly.Instance(module, { "": { getValue: () => 4 } });
    assertEquals(4, instance4.exports.f());
    module = null;
    instance4 = null;
  })();

  // Note that two GC's are required because weak slots clearing is deferred.
  await gc({ type: 'major', execution: 'async' });
  await gc({ type: 'major', execution: 'async' });
})();
